The present invention concerns a ratcheting wrench for driving an element, in particular a bolt or nut, whose head comprises a hexagonal profile. The wrench has an open jaw structure defined by a front jaw and a rear jaw, relative to the driving direction, interconnected by a connecting arch. Each jaw comprises a driving surface adapted to cooperate with respectively a front face and a rear face of the driving profile in the front half of the faces relative to the driving direction. These two faces are opposed, and the jaw structure further comprises on the arch a complementary bearing curved convex protuberance adapted to cooperate, in the absence of torque and in the whole range of the applied driving torques, with a bearing point of the intermediate face of the driving profile situated immediately in front of the rear face relative to the driving direction.
Ratcheting wrenches, or rapid wrenches, are already known which permit the tightening or the untightening of a hexagonal bolt head or nut. They comprise a driving head provided with an open jaw structure in which the hexagonal element is inserted. In the driving direction, two opposite jaws of the jaw structure cooperate with the opposite faces of the hexagonal element for driving the latter. In the direction opposed to the driving direction, the jaws are disengaged from the faces of the hexagonal element and permit free rotation of the wrench about the latter. The driving surfaces of the jaws then slide along the faces of the hexagonal element.
These wrenches are particularly practical and convenient since they permit actuating, in one direction, a hexagonal element, by a simple back and forth movement of the wrench about the latter, and without ever having to completely disengage the head of the wrench from the hexagonal element.
A ratcheting wrench of the aforementioned type is described in the U.S. Pat. No. 3,921,476 in the name of EVANS. This wrench comprises an open jaw structure defined by two opposed jaws adapted to surround a hexagonal element. One of the jaws is provided with a recess for receiving an intersection corner of the six faces. This recess is defined on the jaw by two bosses on each side of the latter. These bosses are adapted to cooperate with areas of two adjacent faces interconnected by the corner received in the recess. These areas are located very close to this corner. Consequently, when the wrench is used, in particular when high torques are applied, the corner of the hexagonal element received in the recess is rapidly deteriorated.